A stage in fat metabolism which is stimulated primarily when the liver is low on glycogen
(stored glucose), although some is happening continually. The breakdown of fats in this process results in three different molecules called ketones or ketone bodies, two of which (acetoacetate and ß-hydroxybutyrate) can be used for fuel by most tissues of the body. Some tissues, such as the heart muscle, prefer ketones to glucose. The third ketone, acetone, cannot be used by the body and is excreted in the urine and breath. The Atkins approach encourages people to monitor this process by testing their urine with a strip called Ketostix (brand name for a product made by Bayer).
Ketosis is not the same thing as ketoacidosis, a dangerous condition that can occur in diabetes.
More Information about Ketosis
Pronunciation: kee TOE sis
Common Misspellings: keytosis
People use Ketostix (or another brand of test strips) to test their urine for ketones, which make the strip turn people. This response is variable, however, and while some people find it helpful and motivating, it is a source of frustration for others.